The temperature coefficient of a capacitor is the maximum change in its capacitance over a specified temperature range.
Ceramic capacitor temperature range.
Capacitors for ac applications are primarily film capacitors metallized paper capacitors ceramic capacitors and bipolar electrolytic capacitors.
The spec for r capacitors such as x5r and x7r is 15.
Class 1 ceramic capacitors.
The temperature coefficient of a capacitor is generally expressed linearly as parts per million per degree centigrade ppm o c or as a percent change over a particular range of temperatures.
Ceramic capacitor dielectrics are defined by a three character eia code that specifies the material s capacitance stability over a specified temperature range.
Some capacitors are non linear.
For instance ceramic capacitors made using x5r dielectric materials have an operating temperature range of 55 c to 85 c with an allowable variation in capacitance of 15 over.
There are two classes of ceramic capacitors available today.
Characteristics precision and tolerances.
Class 1 and class 2.
The second character indicates the maximum temperature.
The third character indicates the maximum amount of capacitance change over the part s temperature range.
Class 3 ceramic capacitors offer higher volumetric efficiency than the class 2 ceramic capacitors but their temperature stability is not nearly so good.
The rated ac load for an ac capacitor is the maximum sinusoidal effective ac current rms which may be applied continuously to a capacitor within the specified temperature range.
5 as in x5r corresponds to 85 c and 7 as in x7r corresponds to 125 c.
Ceramic capacitor dielectrics vary from one manufacturer to another but common compounds include titanium dioxide strontium titanate and barium titanate.
The two most common types are multi layer ceramic capacitors and ceramic disc capacitors.
Only available as leaded components.
A typical performance for the change of capacitance with temperature is 22 to 56 over a range of 10 c to 55 c.
The theoretical range is from 45 c to 200 c.